
'1^3^ 



Subject to Bevision. 

[TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.] 



BUBNISHIJSTG AND DUCTILIZING STEEL. 

BY JACOB REESE, PITTSBURGH, PA. 

(Read at the Philadelphia Meeting, February, 1881.) 

I HAVE discovered a new method by which steel and other metals 
may be burnished by the automatic action of the burnishing machine, 
and by which the cost is greatly diminished, and more perfect work 
produced. And in addition to the polishing and burnishing action of 

Fig. 1. 




<^' Cy' C> ^ 

the new process, I have discovered that by a certain practice in the 
process of burnishing, the metal under treatment may be perma- 
nently increased in diameter of its cross section, and its ductility in- 

1 



</ - 



•P Ui:: 



BUENISHING AND DUCTILIZING STEEL. /C/^ /y^ 



'h 



creased from 30 to 90 per cent., at a temperature ranging from 60^ 
to 250° Fahr. 

Fig. 2. 




ir^The machine is shown in the accompanying drawings, Fig. 1 is a 
top view of a continuous disk-machine, Fig. 2 is an end elevation of 



Fig. 3. 




the same. Fig 3 is a top view of a set of conical disks, and Fig. 4 
is a diagram, showing the working-face of one disk and the back of 
another. Like letters refer to like parts wherever they occur. 



Fig. 4. 




The series of disks, which in the present instance are six in 
number, are arranged so that they all operate upon the bar at one 



BURNISHING AND DUCTILIZING STEEL. 6 

and the same time. The faces of the disks are slightly couical, and 
the centres of the faces are tnrned concave, so that the working-face 
of each disk extends from the edge of the periphery to the outer 
edge or line of the concave portion of the disk. The disks are of 
two sizes, the larger being about sixteen inches in diameter and the 
smaller about fourteen inches. The large disks A A' A^ are placed 
upon the same side of the working-line, and the small disks a a' a^ 
are placed on the opposite side, the object being to secure a down- 
ward bite upon the bar by the large disks and an upward by the 
small disks, thereby keeping the bar down firmly on to the rests. 
These disks are mounted on suitable shafts B B' B^ and 6 b' h', 
which are set in the standards or housings C and C in such a man- 
ner that the large and small disks are not directly opposite to each 
other, but bear such relative positions as will bring the outer edge 
of the working-face of each disk directly opposite to the inner line 
of the working-face of the adjacent disk. This arrangement is not 
absolutely necessary, but renders the construction simpler than other 
modes of arrangement. 

The disk-shafts are provided with pinions D D' D^ and d d' d^, 
which mesh into idlers or pinions mounted on shafts, which are set 
into the standards between each pair of disks. It is necessary to 
have idlers for the disk-pinions to mesh into, because if they were 
to mesh into and communicate motion directly to each other every 
other disk on the same side of the working-line would revolve in an 
opposite direction, and consequently prevent the mechanism from 
working. 

E E' are end housings, provided with suitable adjusting-screws 
for the purpose of setting the machine for any given size of work, to 
adjust the disk-faces in a parallel line and regulate the pressure upon 
the metal operated upon. F indicates the main driving-shaft, 
which is provided with pinions G, g, which mesh into the central 
disk-pinions, D d. H H' H^ indicate rests, which are set in line 
beneath and between the disk-faces. These guides or rests are 
slightly less in width than the diameter of the piece of metal to be 
operated upon, and for ordinary work they are adjusted to keep the 
centre of the bar a little below the centre of the disks, that being 
necessary in order that the resultant action of the forces exerted by 
the movement of the disks may cause the bar to feed forward as it 
rotates. The forward speed will depend upon the altitude of the 
rests in relation to the disk-centres, and if they are adjusted so that 
the centre of the bar is on the same line as the centime of the disks it 



4 BURNISHING AND DUCTILIZING STEEL. 

will rotate, but without forward or backward motion. If the rests 
are adjusted to throw the centre of the bar above the centre of the 
disks, it will have a backward movement as it rotates. 

When power is applied to the main shaft F to rotate the same 
the pinions G g communicate motion to the central disk-pinions D d, 
which turn the idlers, and thus communicate motion to the other 
disk-pinions, causing all the disks to rotate uniformly. In order to 
fit these disks for burnishing and ductilizing iron and steel it is 
necessary that their working-faces should be trued and highly pol- 
ished, and this I accomplish in the following manner: 

The machine having been adjusted for any given size of work and 
the guides or rests being in a line and adjusted to the proper height, 
I take a square ])iece of hard wood of suitable thickness and place 
it upon a rest in front of the machine. I then oil the disk-faces and 
sprinkle them with emery, and finally enter the block between the 
disk-faces, when it will be caught and drawn slowly forward, thus 
truing and polishing the entire train of working-faces at one and the 
same time, and also polishing and truing the working-faces of the 
rests. The machinery is now capable of burnishing and ductilizing 
the metal when properly adjusted for that purpose, and this adjust- 
ment is a matter which will require considerable skill and care upon 
the part of the operator, as a degree of pressure is necessary in some 
cases which would be entirely inadmissible in others. 

By referring to the drawings it will be readily understood that 
when the rests are adjusted to any given height the feeding of the 
bar will be uniform and constant, and therefore the only method of 
increasing and decreasing the frictional action upon the surface of 
the metal will be by regulating the pressure as occasion may require. 
The greater the friction the greater will be the tractive force which 
tends to draw or film the surface of the metal. The ability of the 
metal to resist this drawing force depends upon the attraction of 
cohesion of its particles. This varies in different metals and in the 
same metals at different temperatures, being greatest at the lowest 
and least at the highest temperature ; and in iron and steel it de- 
pends greatly upon the amount of carbon in combination with the 
metal. Now, it is evident that when the bar is put into the machine 
its temperature will be gradually raised by the frictional action at 
each successive pass, and therefore become less and less able to resist 
the tractive force, and that as its temperature increases the metal 
will gradually expand in diameter, so that if all the faces are pre- 
viously adjusted to exactly the same distance apart, not only will 



BURNISHING AND DUCTILIZING STEEL. 6 

the metal become less able to resist the tractive or drawing force, 
but the increased temperature of the metals will, by causing such 
expansion, develop more pressure and frictional tractive force, so 
that the metal will then be very liable to draw or scab. The disk- 
faces should therefore be so adjusted as to bring the greatest pressure 
at the first pass, and to apply a little less at each successive pass 
until the burnished bar is completed. 

In conducting the operation the object is to secure sufficient 
pressure to compress the inequalities and to develop enough fric- 
tional or tractive force to overcome the attraction of cohesion of the 
particles composing the scale on the surface of the metal, yet not 
enough to overcome the force of cohesion of the particles which will 
then form the surface of the metal itself. If the metal has a great 
force of cohesion and does not possess a tough, tenacious scale, 
this may be readily effected ; but where the conditions are 
opposite great care must be had and a constant watch kept 
for signs of filming. Therefore, as it is imperatively necessary that 
certain degrees only of pressure, frictional action, and tractive force 
be applied or developed upon the surface of the metal, it is neces- 
sary, first, that the metal should have been previously rolled to an 
exact or uniform gauge, so that when burnishing an undue amount 
of pressure may not be developed upon its surface at any point; 
secondly, as the ability of the metal to resist the tractive force is less 
when at high temperatures, it should be operated upon when iu a 
cold state, or at a temperature not exceeding 500° F. 

The machine being in condition, having its working-faces trued 
and polished, and the metal having been properly prepared by roll- 
ing to an exact gauge, a test-bar may be entered and the working- 
faces gradually tightened up after each pass until a point is reached 
at which the films begin to show upon its surface. This is an indi- 
cation that the pressure is too great, and the tightening-screws 
should be relieved a little and the test-bar again entered, a careful 
watch being kept for further filming. If none appears the machine 
is properly adjusted for that sized bar; but if films still continue to 
form, the pressure must be further decreased until a point is reached 
at which no films are formed. It is not necessary, however, that the 
machine should always be adjusted in the manner just described, as 
burnished bars may be sometimes produced, although a very light 
pressure is used, as, for instance, where the scale upon the metal is 
not tenacious and the surface of the metal is very smooth ; but in all 
cases the pressure will be light in comparison with that which is 



6 BURNISHING AND DUCTILIZING &TEEL. 

required for rolling and extremely light when compared with that 
required for cold-rolling. I am unable to give the required degree 
which will be necessary in all cases, as I find that the pressure varies 
upon any given point, according to the difference in the diameters of 
the bars operated upon, the larger diameters burnishing under heavier 
pressure than the smaller ; and, moreover, the pressure upon any given 
point may vary accordingly as the width of the burnish ing-faces used 
varies. The wider the disk-faces the greater will be the amount of 
frictional action and tractive force upon any given part of the bar in any 
given time, and consequently the less must be the pressure. The eon- 
verseof the proposition is also true, viz., the narrower the disk-faces the 
less the frictional action and the greater the pressure admissible ; but 
the working-faces must never be made very narrow, as in such case 
so great a pressure would be required to develop the frictional action 
which is necessary that the operation would be entirely changed, and 
cause a reduction of the metal and displacement of its particles, as in 
rolling. Finally, I find that the pressure may vary with the diifer- 
ent temperatures and natures of the metal operated upon. There- 
fore, no precise rule can be adhered to for all cases, except, first, to 
have all stock previously rolled to a uniform gauge; secondly, to 
have all the burnishing-faces turned perfectly true with a high polish ; 
thirdly, to have the burnishing-faces constructed of sufficient width to 
develop a sufficient amount of frictional action when a light pressure is 
applied. Then feed the bar at a proper temperature, and apply the 
pressure from an exceedingly light one to the highest the metal will 
stand without filming. 

The machine being in the condition specified and adjusted as spe- 
cified, rough bars of metal in a cold state are inserted, one at a time, 
between the receiving-disks. They are caught, rotated rapidly, and 
drawn forward, travelling forward with a speed of from one to sixty 
feet per minute, according to the size of the bar, height of the rests, 
and speed at which the disks rotate, and are delivered .perfectly 
straight, of a true cylindrical form and highly burnished. In some 
cases, however, when the bars are of a large diameter, and are cov- 
ered with a tough, tenacious scale, additional passes may be required 
to accomplish this result. 

When burnishing cold metallic bars I prefer to place narrow 
pans, containing petroleum or other oil, beneath the second and 
third pair of disks. These pans are of sufficient size to contain the 
required quantity of oil, and are shaped so as to form a sheath or 
trough, in which the lower portions of the disks revolve. The effect 



BURNISHING AND DUCTILIZING STEEL. 7 

of the application of the oil is to prevent the working-faces of the 
disks from scratching and marring, and it also has a certain eifect 
upon the finished product, of which I shall speak hereafter. 

When it is designed to straighten and burnish metal directly as it 
comes from the rolls during its manufacture, the process should be 
the same as before specified, except that the metal should be allowed 
to cool to a dark red heat, and a considerable quantity of water 
should be let upon the first set of disks and upon the bar, to reduce 
the temperature of the metal to the proper degree, so that in its rapid 
contraction the scale will be loosened. A steam or air blast should 
be used to carry the scale away, and the first and second set of disks 
will then readily remove any portion of scale which may still adhere 
to the bar. The metal will then pass from the first to the second set 
of disks, thoroughly cleaned and partially burnished, and the second 
and third pair of disks will, by the frictional action, which also 
burnishes, heat the surface of the bar. Consequently, the lighter 
components of the oil will be vaporized, leaving the bar coated with 
carbonaceous matter, which is apparently forced into the pores of the 
metal by the action of the disks, and the bar, when burnished, is 
found to have a much finer appearance than if it had been burnished 
without the oil, and it is also enabled to resist oxidation to a greater 
degree. 

For the purpose of illustrating the frictional action which may be 
obtained by the employment of disk-rolls, I will again refer to the 
drawings, in which Fig. 3 represents a top view, and Fig. 4 is a 
diagram, of a set of disk-rolls, the latter showing the back of a 
sixteen-inch and the working-face of a fourteen-inch disk. V indi- 
cates the concave portion of the disk-faces, which is five inches in 
diameter in the fourteen and seven inches in diameter in the sixteen- 
inch disk. X indicates the inner lines or edges of the working- 
faces ; z the neutral lines, or those portions of the disks at which 
their rate of speed when working is equal to the surface speed of the 
bar in rotating; and y the outer edges or lines of the working- 
faces of the disks at their peripheries. It is well understood that 
the different portions of the disk-faces travel at different rates of 
surface speed, according to their position with relation to the disk- 
centres. 

When a cylindrical bar is fed into the disks it will rotate, and, all 
portions of the surface of the bar being at the same distance from the 
axis or centre, will travel at the same surface rate of speed, and as 
the working-faces of the disks travel, having differential rates of 



8 BURNISHINa AND DUCTILIZING STEEL. 

surface speed, as before stated, great frictional action is produced on 
the working-surface of tlie disks and the surface of the bar; or, in 
other words, this result follows because the surface speed of the bar 
and disk- faces is the same only on the theoretical or neutral lines 
indicated by the letter z, the disk-faces travelling at a gradually 
increasing speed from the neutral line to the peripheries, and at a 
gradually decreasing speed from the neutral line to the inner lines 
of the working-faces of the disks. If, therefore, as in ordinary 
practice, the working-faces of the disks are four inches in width 
from the outer to the inner edges of the working-faces, the area of 
the small disk will be 113yqqq- square inches, and that of the large 
disk 138y^-y^ square inches, thus making a total area of 2b\^-^-^^ 
square inches of frictional surface which slips or rubs over the 
surface of the bar at each revolution of the disks. 

In addition to the frictional action of the disk there is that of the 
rests. A bar one and one-eiglith inch in diameter will rotate (the 
rests being at the proper height) eight times to each revolution of 
the disks and feed forward about two inches to each revolution of 
the disks, or one-quarter of an inch to each revolution around its 
own axis. The length of the rest's working-surface is usually about 
five inches, so that the bar will revolve twenty times over the pol- 
ished surface of the rest during the time any given portion of it 
passes from one end to another of the rest, and the rest acts the same 
as if the bar were rotated in a lathe and a burnishing-tool pressed 
against it with the same degree of force during twenty revolutions 
around its axis. Finally, there is the frictional action which arises 
from the forward movement of the bar over the burnishing disks 
and rests. 

One of the effects produced by the frictional action to which I 
have referred, or by the action of the heat developed by the friction, 
is to gradually expand the metal during the burnishing operation, 
so that as the bar travels forward the pressure will become aug- 
mented, unless the tightening-screws are adjusted lighter for the 
latter passes ; and I have found that, when they are properly ad- 
justed, the metal will in some cases retain permanently its increased 
diameter, which I have found in all cases to indicate a slightly de- 
creased tensile strength, elastic limit, and a greatly increased duc- 
tility in the metal. When, however, the tightening-screws were 
adjusted so as to compel the bar to retain its original diameter, I 
have found the elastic limit and ductility are the same as in the 



BURNISHING AND DUCTILIZING STEEL. 9 

original state, and that the tensile strength remains almost the same 
as in the original state previous to the operation. 

The following record of tests made by tension shows clearly the 
changes which are effected in the physical nature of the metal by 
the process : 



Marks and Condition 
of Pieces. 


c ^ 

-5 


i . 

is 


c 
_ o 

11 


.11 


a 

1 
S 




a 

£ 
n 
H 


■5 a 

6C-.2 

S c S 
H O 


a . 
"cl 

Si u 

p > 


a 

1 

a 
o 

M 

Per 

Cent. 


In. 


In.. 


Sq. 
In. 


Sq. 
In. 


Pounds. 


Pounds. 


Pounds. 


Pounds. 


In. 


459 
Rough, 


1.013 


.955 


.806 


.716 


51,000 


63,283 


88,235 


109,486 


.547 


10.94 


460 
Bright 


1.014 


.853 


.807 


.571 


47,500 


58,823 


86,795 


107,486 


.953 


19.06 


461 
Bright, 


1.016 


.851 


.811 


.569 


49,500 


61,058 


88,395 


109,035 


.797 


15.94 


462 
Bright 


1.012 


.969 


.804 


.737 


48,000 


59,674 


88,305 


109,782 


.500 


10.00 


463 
Bright, 


1.015 


.910 


.809 


.650 


47,500 


58,704 


87,365 


107,972 


.656 


13.12 






464 
Bough, 


1.012 


.952 


.804 


.712 


48,000 


59,674 


87,500 


108,782 


.500 


10.00 



Nos. 459, 460, and 461 were cut from the same bar of steel. No. 
459 was cut from the rough end, which was in the same condition 
as it came from the rolling-mill. Nos. 460 and 461 were bright, 
and were cut from the end that had been burnished. No. 459 broke 
just above the top centre punch-mark. No. 460 broke between the 
points of measurement. No. 461 broke at the top centre punch- 
mark. 

Nos. 462, 463, and 464 were cut from one bar of steel, each end 
of which had been burnished. No. 464 was cut from the middle of 
the bar, which was rough as it came from the rolling-mill. No. 462 
was cut from one end, and No. 463 from the other end, both of which 
had been burnished. No. 462 broke one and one-half inch above 
the top centre punch-mark. No. 463 broke one-half inch below the 
top centre punch-mark. No. 464 broke one inch above the top 

2 



10 BURNISHING AND DUCTILIZING STEEL. 

centre punch-mark. No. 462 did not break at its smallest diameter, 
which was midway between the points of measurements. 

All the changes or phenomena which present themselves in the 
finished product show that the operation to which it has been sub- 
jected embodies some principle which has never before shown its 
effects in the product of any rolling, hammering, or compressing 
operation, nor in the product of any burnishing, brightening, or 
polishing operation known heretofore to the art of metallurgy. For 
instance, that indicated by the permanent increase in the diameter 
of the metal, although at the time it is confined between parallel 
surfaces and under-pressure, the operation being conducted so that 
the heat developed does not generally exceed 250° Fahrenheit, which 
would not be sufficient, no matter how long continued, to anneal or 
ductilize heavy cold bars of steel by any known process. 

When steel is required for structural [mrposes it must be able to 
resist concussion sudden shocks, rapid vibration, and deflection, 
and give due warning, before final rupture takes place, by elongat- 
ing within certain degrees. Consequently, heretofore, the steel has 
been made low in carbon to secure the required ductility, and there- 
fore possessed a low tensile strength. This steel is annealed after 
its manufacture, to bring it back to its normal condition, and destroy 
in a measure the effects produced in its physical structure by the ordi- 
nary rolling operation, since all rolling, hammering, and drawing 
leave the physical structure of the metal in an abnormal condition, 
producing hardness, brittleness, and liability to rupture from con- 
cussion, vibration, or rapid deflection. 

Annealing steel reduces its ability to resist tensile, compressive, 
and torsional strain, as well as its elastic limit, and increases its 
elongation or ductility. It is a slow operation, lasting generally 
from five to twenty-four hours, and leaves the metal covered with 
scale. By my process the ductility of the metal may be greatly 
increased without the formation of a scale upon its surface, and in a 
very rapid manner. In comparing it with ordinary annealing opera- 
tions the following facts become apparent: 

First. As the metal is previously rolled to an exact size, and the 
disk-faces are adjusted to exert exactly the same degree of pressure 
and frictional action upon all parts of the bar, the ductility of the 
metal should be constant and uniform at all points, whereas in an- 
nealing the temperature of the furnace varies at different parts, con- 
sequently the metal cannot be uniformly annealed. 



BURNISHING AND DUCTILIZINQ STEEL. 11 

Second. As the bars are all of the same size previous to the burn- 
ishing operations, the same degree of ductilizing action should be 
had upon each, and consequently they should all be regularly duc- 
tilized, whereas in annealing the process is not automatic, and the 
bars are charged and drawn by hand, so that they are exposed to 
heat for irregular periods of time. 

Third. The ductilizing eflPect is produced by this process at a heat 
never exceeding 500° Fahrenheit, and this is too low to deprive the 
bar of carbon ; or, if it does so to any extent, it does it uniformly, 
whereas in annealing the bar loses considerable carbon, and loses it 
unequally, so that not only is the tensile strength reduced consider- 
ably, but it varies at different points of the bar. 

Fourth. As the ductilizing of the metal is constant and uniform, 
its internal strains should be regularly and uniformly relieved, 
whereas in annealing the temperature always varies in different 
parts of the bar; hence its internal strains should be irregularly 
relieved. 

Fifth. As the temperature in this process is very low and uniform 
upon all parts of the bar it remains perfectly straight in cooling, 
whereas in annealing the high and uneven temperature of the metal 
causes it to warp and become distorted in cooling. 

Sixth. By my process I am enabled to ductilize metal at the rate 
of one foot per second to one foot per minute, whereas annealing 
operations require several hours or days for their completion. 

This process will be found to be peculiarly adapted to the produc- 
tion of steel shafting, piston-rods, and also for very light work, such 
as burnished steel for pivots for watches and clocks, etc., in which 
latter case it is evident that the mechanism employed must be of a 
reduced size suitable for the work to be accomplished. 

Comparing the mechanical effect of this process, with other well- 
known processes, the difference is very marked. Wrought iron pos- 
sessing a tensile sti^ength of 50,000 pounds per square inch, and an 
elastic limit of 30,000 pounds per square inch, and exhibiting an 
elongation of 25 per cent., will, when cold-rolled by the Lauth pro- 
cess, possess a tensile strength of 68,600 pounds, and an elastic limit 
of 59,600 pounds, but the ductility is reduced to an elongation of 
6 per cent. When such cold-rolled iron is annealed it is found to 
possess a tensile strength of 48,700 pounds, an elastic limit of 32,000, 
and an elongation of 15 per cent. 

Professor R. H. Thurston, in his paper on " Mechanical Treatment 



12 



BURNISHING AND DUCTILIZING STEEL. 



of Metals,"* said : '^ All known and actually practiced methods of so 
altering the character of the metals used by the engineer, involve, 
directly or indirectly, the elevation of the original elastic limit of 
the material." In this process, however, the elastic limit is slightly 
reduced. 

In conclusion I would add, that the phenomena exhibited in this 
process are not explicable by any of the laws of molecular physics 
known to me. 

* Metallurgical Keview, vol. i, page 1. 



LIBRARY OF CONGRESS 



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LIBRARY OF CONGRESS 

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